These entries match the default instantiated entries from passwd(4). The list of
default entries typically contains the superuser root and other administrative and system application
identities.

The root entry is included in the ftpusers file as a security
measure since the default policy is to disallow remote logins for this
identity. This policy is also set in the default value of the
CONSOLE entry in the /etc/default/login file. See login(1). If you allow root login
privileges by deleting the root entry in ftpusers, you should also modify
the security policy in /etc/default/login to reflect the site security policy for remote
login access by root.

Other default entries are administrative identities that are typically assumed by system
applications but never used for local or remote login, for example sys
and nobody. Since these entries do not have a valid password field
instantiated in shadow(4), no login can be performed.

If a site adds similar administrative or system application identities in passwd(4)
and shadow(4), for example, majordomo, the site should consider including them in
the ftpusers file for a consistent security policy.

Lines that begin with # are treated as comment lines and are
ignored.

Files

/etc/ftpd/ftpusers

A file that lists users for whom ftp login privileges are disallowed.

/etc/ftpusers

See /etc/ftpd/ftpusers. This file is deprecated, although its use is still supported.